There's more to it than just disaffection:
More than three-quarters of the growth in voter registrations in North Carolina this year was among unaffiliated rather than signing up as a Republican, Democrat or Libertarian.
This isn't a new trend. Between voters fed up with either party and unsure of which camp they belong in, the ranks of unaffiliated voters have been growing steadily over the past decade.
This is not limited to NC. As a matter of fact, NC is just now catching up with average national numbers. And while disaffection with the two established parties is definitely a factor, Individuation (with a sprinkling of Narcissism) is likely driving the trend more: